Detection of a protective cover film on a capacitive touch screen

ABSTRACT

Methods, systems, and devices for detection of a protective cover film on a capacitive touch screen are described. A device may include a capacitive touch screen having a surface and a sensor grid underneath the surface having a set of conductive columns and a set of conductive rows. The device may measure a mutual capacitance between a subset of conductive columns or a subset of conductive rows associated with a sensor grid, and compare the measured mutual capacitance between the subset of conductive columns or the subset of conductive rows to a baseline mutual capacitance associated with the set of conductive columns and the set of conductive rows. According to the comparison, the device may determine a presence of a protective layer in contact with the surface of the capacitive touch screen, and adjust an operating characteristic of the sensor grid.

CROSS REFERENCE

The present Application for Patent is a Continuation of U.S. patentapplication Ser. No. 16/899,174 by WITHERS, et al., entitled “DETECTIONOF A PROTECTIVE COVER FILM ON A CAPACITIVE TOUCH SCREEN” filed Jun. 11,2020, which claims the benefit of U.S. patent application Ser. No.16/228,037 by WITHERS, et al., entitled “DETECTION OF A PROTECTIVE COVERFILM ON A CAPACITIVE TOUCH SCREEN,” filed Dec. 20, 2018, assigned to theassignee hereof, and expressly incorporated herein.

BACKGROUND

Some example devices, such as smartphones, may have an interfaceallowing individuals to access features of the smartphone. An example ofan interface may include, but is not limited to, a resistancetouch-based interface, a capacitance touch-based interface, a surfaceacoustic wave-based interface, an optical touch-based interface, anelectromagnetic guidance-based interface, among others. Althoughgenerally durable, these interfaces are susceptible to unforeseendamage. Therefore, increasing demand for products protecting theinterface has influenced the advances made to protective filmmanufacturing. In the example above, the interface may have a protectivefilm (e.g., a transparent film) installed across it to reduce damage tothe interface. While the protective film reduces damage to the interfacein case of impact, the protective film may affect the functionality ofone or more sensors positioned below the interface. For example, aprotective film may defocus ultrasonic fingerprint sensors that may belocated underneath the interface.

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support detection of a protective cover film on acapacitive touch screen. A device may determine a presence of theprotective cover film by measuring a mutual capacitance. For example, acapacitance-based interface may include an array of conductive rows andan array of conductive columns. A change in the mutual capacitancebetween neighboring columns or neighboring rows can be measured todetermine the presence of a protective cover film on the interface. Insome examples, this change can be measured using a lookup table forbaseline capacitance values, along with other information (e.g.,temperature). In this way, the presence of the protective cover film canbe detected without an external input (e.g., a finger touch by anindividual). By determining the presence of the protective film,corrective measures can be applied to the functionality of one or moresensors positioned below the interface (e.g., an ultrasonic fingerprintsensor).

A method is described. The method may include measuring a mutualcapacitance between a subset of conductive columns or a subset ofconductive rows associated with a sensor grid, comparing the measuredmutual capacitance between the subset of conductive columns or thesubset of conductive rows to a baseline mutual capacitance associatedwith the set of conductive columns and the set of conductive rows,determining a presence of a protective layer in contact with a surfaceof the capacitive touch screen based on the comparison, and adjusting anoperating characteristic of the sensor grid based on the presence of theprotective layer in contact with the surface of the capacitive touchscreen.

An apparatus is described. The apparatus may include a processor, acapacitive touch screen in electronic communication with the processor,the capacitive touch screen comprising a surface and a sensor gridunderneath the surface having a set of conductive columns and a set ofconductive rows, memory in electronic communication with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to measure a mutualcapacitance between a subset of conductive columns or a subset ofconductive rows associated with the sensor grid, compare the measuredmutual capacitance between the subset of conductive columns or thesubset of conductive rows to a baseline mutual capacitance associatedwith the set of conductive columns and the set of conductive rows,determine a presence of a protective layer in contact with the surfaceof the capacitive touch screen based on the comparison, and adjust anoperating characteristic of the sensor grid based on the presence of theprotective layer in contact with the surface of the capacitive touchscreen.

Another apparatus is described. The apparatus may include means formeasuring a mutual capacitance between a subset of conductive columns ora subset of conductive rows associated with a sensor grid, comparing themeasured mutual capacitance between the subset of conductive columns orthe subset of conductive rows to a baseline mutual capacitanceassociated with the set of conductive columns and the set of conductiverows, determining a presence of a protective layer in contact with asurface of the capacitive touch screen based on the comparison, andadjusting an operating characteristic of the sensor grid based on thepresence of the protective layer in contact with the surface of thecapacitive touch screen.

A non-transitory computer-readable medium storing code is described. Thecode may include instructions executable by a processor to measure amutual capacitance between a subset of conductive columns or a subset ofconductive rows associated with a sensor grid, compare the measuredmutual capacitance between the subset of conductive columns or thesubset of conductive rows to a baseline mutual capacitance associatedwith the set of conductive columns and the set of conductive rows,determine a presence of a protective layer in contact with a surface ofthe capacitive touch screen based on the comparison, and adjust anoperating characteristic of the sensor grid based on the presence of theprotective layer in contact with the surface of the capacitive touchscreen.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, adjusting the operatingcharacteristic of the sensor grid may include operations, features,means, or instructions for identifying a set of calibration valuescorresponding to the protective layer, and adjusting a sensitivity orlinearity of the sensor grid based on the set of calibration values.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for mapping the measuredmutual capacitance to a first lookup entry in a set of lookup entries,where the set of lookup entries includes a set of classes of protectivelayers and a mutual capacitance corresponding to each class ofprotective layers, and identifying a class of the protective layer basedon the mapping, where adjusting the operating characteristic of thesensor grid may be further based on the class of the protective layer.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for mapping the class ofthe protective layer to a second lookup entry in the set of lookupentries, where the set of lookup entries includes a set of calibrationvalues to compensate for a difference between the measured mutualcapacitance and the baseline mutual capacitance, and calibrating thesensor grid based on the set of calibration values, where adjusting theoperating characteristic of the sensor grid may be further based on thecalibration.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for mapping the measuredmutual capacitance to a second lookup entry in the set of lookupentries, where the set of lookup entries includes a layer thicknesscorresponding to the mutual capacitance of each class of protectivelayers, and estimating a layer thickness of the protective layer basedon the mapping, where identifying the class of the protective layer maybe further based on the estimated thickness of the protective layer.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for mapping the estimatedlayer thickness of the protective layer to a third lookup entry in theset of lookup entries, where the set of lookup entries further includesa set of calibration values to compensate for a difference between themeasured mutual capacitance and the baseline mutual capacitance, andcalibrating the sensor grid based on the set of calibration values,where adjusting the operating characteristic of the sensor grid may befurther based on the calibration.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining an ambienttemperature associated with the measured mutual capacitance between thesubset of conductive columns or the subset of conductive rows, andcomparing the ambient temperature associated with the measured mutualcapacitance to a baseline temperature associated with the baselinemutual capacitance, where adjusting the operating characteristic of thesensor grid may be further based on the comparison between the ambienttemperature associated with the measured mutual capacitance and thebaseline temperature associated with the baseline mutual capacitance.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a mutualcapacitance offset value based on the comparison, and mapping the mutualcapacitance offset value to a second lookup entry in the set of lookupentries, where the set of lookup entries includes a set of calibrationvalues to compensate for the mutual capacitance offset value associatedwith a difference between the ambient temperature associated with themeasured mutual capacitance and the baseline temperature associated withthe baseline mutual capacitance, where adjusting the operatingcharacteristic of the sensor grid may be further based on the mutualcapacitance offset value.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for calibrating the sensorgrid based on the set of calibration values, where adjusting theoperating characteristic of the sensor grid may be further based on thecalibration.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for determining a presenceof a second protective layer in contact with the surface of thecapacitive touch screen based on the comparison, where adjusting theoperating characteristic of the sensor grid may be further based on thepresence of the protective layer and the second protective layer incontact with the surface of the capacitive touch screen.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the protective layer may bein contact with a first region of the surface of the capacitive touchscreen and the second protective layer may be in contact with a secondregion of the surface of the capacitive touch screen different from thefirst region.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for measuring a touchcapacitance associated with a touch-point in contact with the surface ofthe capacitive touch screen, adding the touch capacitance to themeasured mutual capacitance, and comparing the measured mutualcapacitance including the touch capacitance to the baseline mutualcapacitance, where determining the presence of the protective layer incontact with the surface of the capacitive touch screen may be furtherbased on the comparison of the measured mutual capacitance including thetouch capacitance to the baseline mutual capacitance.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the protective layer includesat least one of a polyimide, a polyethylene, a terephthalate, apolyethylene terephthalate polyester, a polyurethane, or a pressuresensitive adhesive, or a combination thereof.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the baseline mutualcapacitance may be a manufacturing defined mutual capacitance associatedwith the set of conductive columns and the set of conductive rows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system that supports detection of aprotective cover film on a capacitive touch screen in accordance withaspects of the present disclosure.

FIG. 2 illustrates an example of a block diagram including a device thatsupports detection of a protective cover film on a capacitive touchscreen in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a method that supports detection of aprotective cover film on a capacitive touch screen in accordance withaspects of the present disclosure.

FIGS. 4 and 5 show block diagrams of devices that support detection of aprotective cover film on a capacitive touch screen in accordance withaspects of the present disclosure.

FIG. 6 shows a block diagram of an operations manager that supportsdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure.

FIG. 7 shows a diagram of a system including a device that supportsdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure.

FIGS. 8 through 11 show flowcharts illustrating methods that supportdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION

A device, for example, such as smartphones, may have an interfaceallowing individuals to access features of the smartphone. The interfacemay include, but is not limited to a resistance touch-based interface, acapacitance touch-based interface, a surface acoustic wave-basedinterface, an optical touch-based interface, an electromagneticguidance-based interface, among others. In some examples, the device mayhave one or more protective cover films (e.g., a transparent film)installed across it to reduce possible damage to the interface. Althoughthe one or more protective cover films may reduce damage to theinterface, these films may disturb the functionality of one or moresensors positioned below the interface.

To appreciate the benefits of the present disclosure and address theshortcoming of standing techniques, the device may support detection ofone or more protective cover films present on an interface of thedevice, and adjust an operating characteristic of the one or moresensors positioned below the interface. For example, the device maymeasure a mutual capacitance between a subset of conductive columns or asubset of conductive rows associated with the one or more sensorsunderneath the interface, and compare the measured mutual capacitancebetween the subset of conductive columns or the subset of conductiverows to a baseline mutual capacitance (e.g., a manufacturing definedmutual capacitance) associated with the set of conductive columns andthe set of conductive rows. As a result, the device determine a presenceof a protective layer in contact with the interface, and adjust asensitivity or linearity of the one or more sensors.

Therefore, the techniques described herein may provide improvements indetection of one or more protective cover films on the interfaceassociated with the device. Furthermore, the techniques described hereinmay provide benefits and enhancements to the operation of the device(e.g., improved sensitivity or linearity of the one or more sensorsassociated with and underneath the interface). For example, bysupporting effective techniques for detection of one or more protectivecover films, the operational characteristics, such as power consumption,processor utilization, and memory usage of the device may be reduced.The techniques described herein may also provide efficiency to thedevice by reducing latency associated with processes related to thedetection of one or more protective cover films.

Aspects of the disclosure are initially described in the context of awireless communications system. Aspects of the disclosure are furtherillustrated by and described with reference to a device and methods thatrelate to detection of a protective cover film on a capacitive touchscreen. Aspects of the disclosure are further illustrated by anddescribed with reference to apparatus diagrams, system diagrams, andflowcharts that relate to detection of a protective cover film on acapacitive touch screen.

FIG. 1 illustrates an example of a system 100 that supports detection ofa protective cover film on a capacitive touch screen in accordance withaspects of the present disclosure. The system 100 may include devices105, a server 110, and a database 115. Although, the system 100illustrates two devices 105, a single server 110, a single database 115,and a single network 120, the present disclosure applies to any systemarchitecture having one or more devices 105, servers 110, databases 115,and networks 120. The devices 105, the server 110, and the database 115may communicate with each other and exchange information that supportsdetection of a protective cover film on an interface of the devices 105,via network 120 using communications links 125. In some cases, a portionor all of the techniques described herein supporting detection of aprotective cover film on an interface may be performed on the devices105 or the server 110, or both.

The devices 105 may be a cellular phone, a smartphone, a personaldigital assistant (PDA), a wireless communication device, a handhelddevice, a tablet computer, a laptop computer, a cordless phone, adisplay device (e.g., monitors), and/or the like that supports varioustypes of communication and functional features related to detection of aprotective cover film on an interface for example, transmitting,receiving, and storing calibration data 140, protective film data 145,among other data. The devices 105 may, additionally or alternatively, bereferred to by those skilled in the art as a user equipment (UE), a userdevice, a smartphone, a Bluetooth device, a Wi-Fi device, a mobilestation, a subscriber station, a mobile unit, a subscriber unit, awireless unit, a remote unit, a mobile device, a wireless device, awireless communications device, a remote device, an access terminal, amobile terminal, a wireless terminal, a remote terminal, a handset, auser agent, a mobile client, a client, and/or some other suitableterminology. In some cases, the devices 105 may also be able tocommunicate directly with another device (e.g., using a peer-to-peer(P2P) or device-to-device (D2D) protocol). For example, the devices 105may be able to receive from or transmit to another device 105 variety ofinformation, such as instructions or commands (e.g., calibration data140, protective film data 145).

The devices 105 may include an operations manager 135. While, the system100 illustrates only one device 105 including the operations manager135, it may be an optional feature for the devices 105. In someexamples, the devices 105 may have an application that may receiveinformation (e.g., download) from the server 110, database 115 oranother device 115, or transmit (e.g., upload) calibration data 140,protective film data 145, among other data to the server 110, thedatabase 115, or to another device 115 via using communications links125. The operations manager 135 may measure a mutual capacitance betweena subset of conductive columns or a subset of conductive rows associatedwith a sensor grid underneath a surface of an interface having a set ofconductive columns and a set of conductive rows. The interface mayinclude, but is not limited to a resistance touch-based interface, acapacitance touch-based interface, a surface acoustic wave-basedinterface, an optical touch-based interface, an electromagneticguidance-based interface, among others. The operations manager 135 maycompare the measured mutual capacitance between the subset of conductivecolumns or the subset of conductive rows to a baseline mutualcapacitance associated with the set of conductive columns and the set ofconductive rows, and determine a presence of a protective layer incontact with the surface of the interface based at least in part on thecomparison. The protective layer may include at least one of apolyimide, a polyethylene, a terephthalate, a polyethylene terephthalatepolyester, a polyurethane, or a pressure sensitive adhesive, or acombination thereof. As a result, the operations manager 135 may adjustan operating characteristic of the sensor grid. The operatingcharacteristics of the sensor grid may include, but are not limited to,a sensitivity of the sensor grid, a range of the sensor grid, aresolution of the sensor grid, or a linearity of the sensor grid, or anycombination thereof. Therefore, the operations manager 135 may adjust asensitivity, a range, a resolution, an accuracy, or a linearity of thesensor grid. In some examples, the operations manager 135 may adjust theoperating characteristics of the sensor grid including the sensitivityof the sensor grid, the range of the sensor grid, the resolution of thesensor grid, or the linearity of the sensor grid, or any combinationthereof via an application running on the device 105. For example, theoperations manager 135 may adjust an operating characteristics of thesensor grid using a lookup table that includes a set of operatingcharacteristics values for different protective layers, as well asthickness associated with the corresponding protective layers.

A sensitivity of the sensor grid may be defined as a minimum input of aphysical parameter (e.g., a mutual capacitance, a touch capacitance)that creates a detectable output range. In some examples, thesensitivity may be defined as an input parameter change required toproduce a standardized output change. That is, a mutual capacitancechange for a given change in input parameter. The operations manager 135may adjust a sensitivity of the sensor grid based on the protectivelayer in contact with the surface of the interface. The operationsmanager 135 may consult a lookup table that includes a set ofsensitivity values for different protective layers, as well as thicknessassociated with the corresponding protective layers. Therefore, theoperations manager 135 may adjust the sensitivity of the sensor gridaccording to the protective layer, as well as the thickness associatedwith the corresponding protective layer. For example, the operationsmanager 135 may correlate the protective layer to a sensitivity valuefor the sensor grid, and adjust the sensitivity of the sensor grid basedon the sensitivity value.

A range of the sensor grid may be defined as the maximum and minimumvalues of applied parameters (e.g., mutual capacitances) that can bemeasured. The operations manager 135 may adjust a range of the sensorgrid based on the protective layer in contact with the surface of theinterface. The operations manager 135 may consult a lookup table thatincludes a set of range values for different protective layers, as wellas thickness associated with the corresponding protective layers.Therefore, the operations manager 135 may adjust the range of the sensorgrid according to the protective layer, as well as the thicknessassociated with the corresponding protective layer. For example, theoperations manager 135 may correlate the protective layer to a rangevalue for the sensor grid, and adjust the range of the sensor grid basedon the range value.

A resolution of the sensor grid may be defined as the smallestdetectable incremental change of an input parameter (e.g., mutualcapacitance, touch capacitance) that can be detected in an outputsignal. The operations manager 135 may adjust a resolution of the sensorgrid based on the protective layer in contact with the surface of theinterface. The operations manager 135 may consult a lookup table thatincludes a set of resolution values for different protective layers, aswell as thickness associated with the corresponding protective layers.Therefore, the operations manager 135 may adjust the resolution of thesensor grid according to the protective layer, as well as the thicknessassociated with the corresponding protective layer. For example, theoperations manager 135 may correlate the protective layer to aresolution value for the sensor grid, and adjust the resolution of thesensor grid based on the resolution value.

A linearity of the sensor grid may be defined as an expression of theextent to which an actual measured curve of the sensor grid departs fromthe ideal curve. The operations manager 135 may adjust a linearity ofthe sensor grid based on the protective layer in contact with thesurface of the interface. The operations manager 135 may consult alookup table that includes a set of linearity values for differentprotective layers, as well as thickness associated with thecorresponding protective layers. Therefore, the operations manager 135may adjust the linearity of the sensor grid according to the protectivelayer, as well as the thickness associated with the correspondingprotective layer. For example, the operations manager 135 may correlatethe protective layer to a linearity value for the sensor grid, andadjust the linearity of the sensor grid based on the linearity value.That is, the operations manager 135 may adjust the extent to which theactual measured curve of the sensor grid departs from the ideal curve.

The operations manager 135 may be part of a general-purpose processor, adigital signal processor (DSP), a central processing unit (CPU), agraphics processing unit (GPU), a microcontroller, anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA), a discrete gate or transistor logic component, adiscrete hardware component, or any combination thereof) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure, and/or the like. Forexample, the operations manager 135 may process data (e.g., calibrationdata 140, protective film data 145) from and/or write data (e.g.,calibration data 140, protective film data 145) to a local memory of thedevice 105 or to the database 115.

The server 110 may be a data server, a cloud server, a proxy server, aweb server, an application server, a communications server, a homeserver, a mobile server, or any combination thereof. The server 110 mayoptionally store calibration data 140, protective film data 145. Thecalibration data 140 or the protective film data 145, or both may allowthe devices 105 to determine a presence of a protective layer in contactwith a surface of an interface of the devices 105 (e.g., a capacitivetouch screen), which the devices 105 may use to adjust an operatingcharacteristic of a sensor grid underneath the surface of the interfacehaving a set of conductive columns and a set of conductive rows. Theserver 110 may also transmit to the devices 105 a variety ofinformation, such as instructions or commands, for example such ascalibration data 140, protective film data 145, among other data.

The database 115 may store a variety of information, such asinstructions or commands (e.g., calibration data 140, protective filmdata 145, among other data). For example, the database 115 mayoptionally store calibration data 140, protective film data 145, amongother data. The devices 105 may retrieve the stored data from thedatabase 115 via the network 120 using communication links 125. In someexamples, the database 115 may be a relational database (e.g., arelational database management system (RDBMS) or a Structured QueryLanguage (SQL) database), a non-relational database, a network database,an object-oriented database, among others that stores the variety ofinformation, such as instructions or commands (e.g., calibrationinformation).

The network 120 may provide encryption, access authorization, tracking,Internet Protocol (IP) connectivity, and other access, computation,modification, and/or functions. Examples of network 120 may include anycombination of cloud networks, local area networks (LAN), wide areanetworks (WAN), virtual private networks (VPN), wireless networks (using802.11, for example), cellular networks (using third generation (3G),fourth generation (4G), long-term evolved (LTE), or new radio (NR)systems (e.g., fifth generation (5G) for example), etc. Network 120 mayinclude the Internet.

The communications links 125 shown in the system 100 may include uplinktransmissions from the device 105 to the server 110 and the database115, and/or downlink transmissions, from the server 110 and the database115 to the device 105. The wireless links 125 may transmit bidirectionalcommunications and/or unidirectional communications. In some examples,the communication links 125 may be a wired connection or a wirelessconnection, or both. For example, the communications links 125 mayinclude one or more connections, including but not limited to, Wi-Fi,Bluetooth, Bluetooth low-energy (BLE), cellular, Z-WAVE, 802.11,peer-to-peer, LAN, wireless local area network (WLAN), Ethernet,FireWire, fiber optic, and/or other connection types related to wirelesscommunication systems.

The techniques described herein may provide improvements in detection ofa protective cover film on a surface of an interface (e.g., a resistancetouch-based interface, a capacitance touch-based interface, a surfaceacoustic wave-based interface, an optical touch-based interface, anelectromagnetic guidance-based interface, among others). Furthermore,the techniques described herein may provide benefits and enhancements tothe operation of the devices 105 (e.g., improved sensitivity orlinearity of a sensor grid associated with the interface). By supportingefficient and effective techniques for detection of a protective coverfilm, the operational characteristics, such as power consumption,processor utilization (e.g., CPU processing utilization), and memoryusage of the devices 105 may be reduced. For example, by use of one ormore lookup tables, the device 105 may identify calibration values toimprove the operability of the sensor grid associated with the device105 in an efficient manner; for example, rather than having to calculatethe calibration values itself. The techniques described herein may alsoprovide efficiency to the devices 105 by reducing latency associatedwith processes related to the detection of a protective cover film.

FIG. 2 illustrates an example of a block diagram 200 including a device105-a that supports detection of a protective cover film on a capacitivetouch screen in accordance with aspects of the present disclosure. Thedevice 105-a may be examples of the corresponding devices 105 describedwith reference to FIG. 1. The device 105-a may include an interface 210,which may include, but is not limited to a capacitance touch-basedinterface. Alternatively, the interface 210 may include, but is notlimited to, a resistance touch-based interface, a capacitancetouch-based interface, a surface acoustic wave-based interface, anoptical touch-based interface, an electromagnetic guidance-basedinterface, among others. In some examples, the device 105-a mayimplement aspects of the system 100. For example, while generallyrobust, the interface 210 may be susceptible to unforeseen damage.Therefore, increasing demand for products protecting the interface 210has influenced the advances made to protective film manufacturing. Inthe example of FIG. 2, the interface 210 may have one or more protectivecover films 215 (e.g., a transparent film) installed across it to reducedamage to the interface 210 of the device 105-a. Although the one ormore protective cover films 215 may reduce damage to the interface 210,the one or more protective cover films 215 may disturb the functionalityof a sensor grid 205 (e.g., having one or more sensors) positioned belowthe interface 210.

The sensor grid 205 may have a certain geometrical grid pattern that mayhave an effect on spatial accuracy and noise resistance of touch sensingrelated to the interface 210. In capacitance touch-based interface, thesensor grid 205 may include a set of conductive columns 220 and a set ofconductive rows 225. In some examples, the set of conductive columns 220or the set of conductive rows 225, or both may be formed from anelectrode having same or different characteristics. In an example, theset of conductive columns 220 may be formed of a positive electrode,while the set of conductive rows 225 may be formed of a negativeelectrode, or vice versa. Examples of positive electrode materials mayinclude LiCoO₂, LiNi_(0.8)Co_(0.15)Al_(0.05)O₂,LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂, and LiFePO₄, while examples of negativeelectrode materials may include graphite and Li₄Ti₅O₁₂.

Some examples of surface capacitance sensor grids may include projectedcapacitive touch (PCT), which may include self-capacitance and mutualcapacitance. For mutual capacitance, the sensor grid 205 may have acapacitor 230 at each intersection of each row and column of the sets. Avoltage may be applied to the columns 220 or the rows 225 of the set. Bybringing a finger or conductive stylus near a surface of the sensorunderneath the interface 210 may change a local electric field that mayreduce a mutual capacitance across a capacitor 230 at an intersection ofa column 220 and a row 225 of the set. The capacitance change at everyindividual point on the sensor grid 205 may be measured to accuratelydetermine a touch location by measuring a voltage in the other axis. Assuch, mutual capacitance allows multi-touch operation where multiplefingers, palms or styli can be accurately tracked at the same time.Alternatively, for self-capacitance, the sensor grid 205 may also have acapacitor 230 at each intersection of each column 220 and row 225 of thesets, however, in this case the columns 220 and rows 225 may operateindependently. That is, with self-capacitance, the sensor gird 205 maysense a current on the capacitive load of a finger on each column 220 orrow 225 of the set. This produces a higher signal than in the mutualcapacitance sensing, but it is unable to resolve accurately more thanone finger, which results in misplaced location sensing.

The device 105-a may determine a presence of one or more protectivecover films 215 in contact with a surface of the interface 210 based onmutual capacitance measurements or self-capacitance measurements. Forexample, the device 105-a may measure a mutual capacitance between asubset of conductive columns 220 or a subset of conductive rows 225associated with the sensor grid 205. Upon measuring the mutualcapacitance, the device 105-a may compare the measured mutualcapacitance between the subset of conductive columns 220 or the subsetof conductive rows 225 to a baseline mutual capacitance. The baselinemutual capacitance may be a manufacturing defined mutual capacitanceassociated with the set of conductive columns 220 and the set ofconductive rows 225. For example, a manufacturing defined mutualcapacitance may be a baseline mutual capacitance value (e.g. in Farads)of a mutual capacitance across a capacitor 230 at an intersection ofeach column 220 and each row 225 of the set. In some examples, thedevice 105-a may additionally, or alternatively measure a touchcapacitance associated with a touch-point in contact with the surface ofthe interface 210. In this example, the device 105-a may add the touchcapacitance to the measured mutual capacitance, and compare the measuredmutual capacitance including the touch capacitance to the baselinemutual capacitance.

According to the comparisons, the device 105-a may determine a presenceof the one or more protective cover films 215 in contact with thesurface of the interface 210. The one or more protective cover films 215may include a polyimide, a polyethylene, a terephthalate, a polyethyleneterephthalate polyester, a polyurethane, or a pressure sensitiveadhesive, or a combination thereof. In some examples, the device 105-amay determine a presence of multiple protective cover films 215 based onthe measured mutual capacitance. For example, the device 105-a maydetermine a presence of a first protective cover film 215, oradditionally presence of a second protective cover film 215 in contactwith and above the first protective cover film 215. Each additionallayer of protective cover film 215 may affect (e.g., increase) themeasured mutual capacitance, while each exclusion of the protectivecover film 215 may decrease the measured mutual capacitance. In someexamples, the first protective cover film 215 may be in contact with afirst region of the surface of the interface 210 and the secondprotective cover film 215 may be in contact with a second region of thesurface of the interface 210 different from the first region. That is,both the first protective cover film 215 and the second protective coverfilm 215 may be on a same level (e.g. layer, plane) of the surface ofthe interface 210, but occupy different regions of the surface of theinterface 210.

To mitigate the impact of the protective cover film(s) 215 on thefunctionality of the sensor grid 210, the device 105-a may adjust anoperating characteristic, such as sensitivity or linearity, of thesensor grid 210. For example, the device 105-a may identify a set ofcalibration values corresponding to the protective cover film(s) 215,and adjust a sensitivity or linearity of the sensor grid 210 using theset of calibration values. In some examples, the device 105-a may mapthe measured mutual capacitance to a first lookup entry in a set oflookup entries, and identify a class of the protective cover film(s)215. The set of lookup entries may include a set of classes ofprotective layers and a mutual capacitance corresponding to each classof protective layers.

The device 105-a may also map the class of the protective layer to asecond lookup entry in the set of lookup entries. In this example, theset of lookup entries may include a set of calibration values tocompensate for a difference between the measured mutual capacitance andthe baseline mutual capacitance. As such, the device 105-a may adjust(e.g., calibrate) the operating characteristic of the sensor grid 205based on the class of the protective layer and corresponding set ofcalibration values associated with the class. In some examples, the setof lookup entries may be part of a lookup table stored locally on thedevice 105-a. For example, a lookup table may be part of a relationaldatabase, a non-relational database, among other databases that stores avariety of information, such as instructions or commands (e.g., classesof protective layers, calibration information).

In an example where multiple protective cover film(s) 215 may be incontact with a first region of the surface of the interface 210 and thesecond protective cover film 215 may be in contact with a second regionof the surface of the interface 210 different from the first region.That is, both the first protective cover film 215 and the secondprotective cover film 215 may be on a same level (e.g. layer, plane) ofthe surface of the interface 210, but occupy different regions of thesurface of the interface 210, the device 105-a may adjust (e.g.,calibrate) the operating characteristic of the sensor grid 205 based onthe class of each corresponding protective cover film 215 andcorresponding set of calibration values associated with the class forthe individual cover film 215. For example, the first protective coverfilm 215 may be associated with a first class of and a first set ofcalibration values associated with the first class, while the secondprotective cover film 215 may be associated with a second class of and asecond set of calibration values associated with the second class.

In some examples, the device 105-a may determine an effective mutualcapacitance associated with the multiple protective cover film(s) 215 toperform the mapping. The device 105-a may also determine the presence ofmultiple protective cover film(s) 215 based on detection of a marker(e.g., an elemental marker), which can be used by the device 105-a toidentity a material (e.g., a polyimide, a polyethylene, a terephthalate,a polyethylene terephthalate polyester, a polyurethane, or a pressuresensitive adhesive) of each protective cover film(s) 215. As a result,the device 105-a may determine presence of multiple protective coverfilm(s) 215 and whether the protective cover film(s) 215 are formed of asame or different material, for example, based on detection of a marker.

In some examples, the device 105-a may map the measured mutualcapacitance to a second lookup entry in the set of lookup entries. Thisset of lookup entries may include a layer thickness corresponding to themutual capacitance of each class of protective layers, which the device105-a may use to estimate a layer thickness of the protective coverfilm(s) 215. The device 105-a may use the estimated layer thickness tomap to a third lookup entry in the set of lookup entries, which mayinclude a set of calibration values to compensate for a differencebetween the measured mutual capacitance and the baseline mutualcapacitance. As such, the device 105-a may additionally, oralternatively calibrate the sensor grid 205 according to an estimatedlayer thickness of the protective cover film(s) 215 and related set ofcalibration values for the thickness. In some examples, the device 105-amay drive frequencies to better map effective thickness and material ofthe protective cover film(s) 215. For example, the device 105-a mayevaluate the amount of absorption, reflection, and transmission of asignal (e.g., sound signal) at different frequencies to determine theeffective thickness and material of the protective cover film(s) 215. Anamount of absorption, reflection, and transmission may map to a certaineffective thickness and material of the protective cover film(s) 215 ina set of lookup entries. The device 105-a may use the effectivethickness and material to map to another lookup entry in the set oflookup entries, which may include a set of calibration values tocompensate for a difference between the measured mutual capacitance andthe baseline mutual capacitance.

In some examples, temperature changes may have a similar or even greatereffect on the mutual capacitance than just presence of the protectivecover film(s) 215, making temperature monitoring and calibrationcompensation desirable. To mitigate the impact of temperature changes onthe functionality of the sensor grid 210, the device 105-a may accountfor the temperature changes to calibrate the senor gird 210. Forexample, the device 105-a may determine an ambient temperatureassociated with the measured mutual capacitance between the subset ofconductive columns 220 and the subset of conductive rows 225, andcompare the ambient temperature associated with the measured mutualcapacitance to a baseline temperature associated with the baselinemutual capacitance. In some examples, the device 105-a may determine amutual capacitance offset value based on the comparison, and map themutual capacitance offset value to a second lookup entry in the set oflookup entries. In this example, the set of lookup entries may include aset of calibration values to compensate for the mutual capacitanceoffset value associated with a difference between the ambienttemperature associated with the measured mutual capacitance and thebaseline temperature associated with the baseline mutual capacitance.Therefore, the device 105-a may adjust an operating characteristic ofthe sensor grid 205, for example, such as a sensitivity or linearity ofthe sensor grid 205 according to the mutual capacitance offset value andthe corresponding set of calibration values.

The techniques described herein may provide improvements in detection ofone or more protective cover film(s) 215 on a surface of the interface210 associated with the device 105-a. Furthermore, the techniquesdescribed herein may provide benefits and enhancements to the operationof the device 105-a (e.g., improved sensitivity or linearity of a sensorgrid associated with and underneath the interface 210). For example, bysupporting efficient and effective techniques for detection of one ormore protective cover film(s) 215, the operational characteristics, suchas power consumption, processor utilization, and memory usage of thedevice 105-a may be reduced. The techniques described herein may alsoprovide efficiency to the device 105-a by reducing latency associatedwith processes related to the detection of one or more protective coverfilm(s) 210.

FIG. 3 illustrates an example of a method 300 that supports detection ofa protective cover film on a capacitive touch screen in accordance withaspects of the present disclosure. In some examples, the method 300 maysupport autodetection of a protective cover film on a capacitive touchscreen and an autocalibration technique. The operations of method 300may be implemented by a device or its components as described herein.For example, the operations of method 300 may be performed by a device105-b or an operations manager 135 as described with reference toFIG. 1. In some examples, the device 105-b may execute a set ofinstructions to control the functional elements of the device 105-b, asdescribed with reference to FIG. 1, to perform the functions describedbelow. Additionally or alternatively, the device 105-b may performaspects of the functions described below using special-purpose hardware.Certain operations may also be left out of the method 300, or otheroperations may be added to the method 300.

At 305, the device 105-b may perform a factory calibration withprotective cover film on a surface of a capacitive touch screen having asensor grid underneath the surface. At 310, the device 105-b may performauto-detection to detect the protective cover film on the surface usinga touch screen sensor underneath the surface of the capacitive touchscreen.

At 315, the device 105-b may perform a first auto-calibration byapplying a first set of sensor tuning offset values retrieved frommemory, for example, as described in FIG. 2 with reference to a set oflookup entries.

At 320, the device 105-b may determine an image quality (IQ) valueassociated with the sensor grid. For example, the device 105-b maydetermine the IQ value using one or more image processing techniques. Inimage processing terms, with reference to FIG. 2, self-capacitancesensors rely on projections much like tomographic imaging, while mutualcapacitance sensors are true pixel array designs capable of forming animage directly. Therefore, the device 105-b may determine presence of aprotective cover film on the surface of capacitive touch screen based onan image associated with the sensor grid and the surface of thecapacitive touch screen surface. For example, the device 105-b maycompare a baseline image associated with a mutual capacitance of thesensor grid without a protective cover film on the surface of thecapacitive touch screen, and a captured image with a protective coverfilm on the surface of the capacitive touch screen.

At 325, the device 105-b may perform a second auto-calibration byapplying a second set of sensor tuning offset values retrieved frommemory. For example, the device 105-b may perform the secondauto-calibration based on the IQ value being below a threshold.Otherwise, if the IQ value is equal to or greater than the threshold, at330, the device 105-b may confirm calibration and match based onmatching a regular version and an inverted version of an image of thesensor grid.

Accordingly, the method 300 may provide improvements in detection of oneor more protective cover film(s) on a surface of capacitive touch screenassociated with the device 105-b. The method 300 may also providebenefits and enhancements to the operation of the device 105-b (e.g.,improved sensitivity or linearity of a sensor grid associated with andunderneath the capacitive touch screen). For example, by supportingefficient and effective techniques for detection of one or moreprotective cover film(s), the operational characteristics, such as powerconsumption and processor utilization, of a sensor grid associated withthe device 105-b may be reduced.

Although the method 300 is described in context of using imageprocessing techniques, other techniques may additionally, oralternatively be supported by the device 105-b to support autodetectionof a protective cover film on a capacitive touch screen and anautocalibration technique. For example, the device 105-b may supportQFS-D background image techniques such as, film signature in air image(e.g., frame, horizontal, vertical lines, other patterns), BGE basiscomparison, BG signal phase, and differential BG images (e.g.,RGD1-RGD2, among others. In another example, the device 105-b maysupport QFS-D finger image techniques such as, US finger-detectionmethod for screen signatures, scanning different tuned conditions anddetection of a best IQ value, autofocus techniques (e.g., factorycalibration with and without offset), determining for FP IQ signature(e.g., IQ metrics, phase), and thermal response, among others. Infurther examples, the device 105-b may support autodetection of aprotective cover film on a capacitive touch screen and anautocalibration technique based on external input (e.g., user input,markers on protective cover films (e.g., magnetic, RFID, etc.), amongothers.

FIG. 4 shows a block diagram 400 of a device 405 that supports detectionof a protective cover film on a capacitive touch screen in accordancewith aspects of the present disclosure. The device 405 may be an exampleof aspects of a device as described herein. The device 405 may include areceiver 410, an operations manager 415, and a transmitter 420. Thedevice 405 may also include a processor. Each of these components may bein communication with one another (e.g., via one or more buses).

The receiver 410 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to detection ofa protective cover film on a capacitive touch screen, etc.). Informationmay be passed on to other components of the device 405. The receiver 410may be an example of aspects of the transceiver 720 described withreference to FIG. 7. The receiver 410 may utilize a single antenna or aset of antennas.

The operations manager 415 may measure a mutual capacitance between asubset of conductive columns or a subset of conductive rows associatedwith a sensor grid, compare the measured mutual capacitance between thesubset of conductive columns or the subset of conductive rows to abaseline mutual capacitance associated with the set of conductivecolumns and the set of conductive rows, determine a presence of aprotective layer in contact with the surface of the capacitive touchscreen based on the comparison, and adjust an operating characteristicof the sensor grid based on the presence of the protective layer incontact with the surface of the capacitive touch screen. The operationsmanager 415 may be an example of aspects of the operations manager 710described herein.

The operations manager 415, or its sub-components, may be implemented inhardware, code (e.g., software or firmware) executed by a processor, orany combination thereof. If implemented in code executed by a processor,the functions of the operations manager 415, or its sub-components maybe executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The operations manager 415, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the operationsmanager 415, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the operations manager 415, or its sub-components, maybe combined with one or more other hardware components, including butnot limited to an input/output (I/O) component, a transceiver, a networkserver, another computing device, one or more other components describedin the present disclosure, or a combination thereof in accordance withvarious aspects of the present disclosure.

The transmitter 420 may transmit signals generated by other componentsof the device 405. In some examples, the transmitter 420 may becollocated with a receiver 410 in a transceiver module. For example, thetransmitter 420 may be an example of aspects of the transceiver 720described with reference to FIG. 7. The transmitter 420 may utilize asingle antenna or a set of antennas.

FIG. 5 shows a block diagram 500 of a device 505 that supports detectionof a protective cover film on a capacitive touch screen in accordancewith aspects of the present disclosure. The device 505 may be an exampleof aspects of a device 405 or a device 115 as described herein. Thedevice 505 may include a receiver 510, an operations manager 515, and atransmitter 540. The device 505 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 510 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to detection ofa protective cover film on a capacitive touch screen, etc.). Informationmay be passed on to other components of the device 505. The receiver 510may be an example of aspects of the transceiver 720 described withreference to FIG. 7. The receiver 510 may utilize a single antenna or aset of antennas.

The operations manager 515 may be an example of aspects of theoperations manager 415 as described herein. The operations manager 515may include a measurement component 520, a comparison component 525, adetermination component 530, and an adjustment component 535. Theoperations manager 515 may be an example of aspects of the operationsmanager 710 described herein.

The measurement component 520 may measure a mutual capacitance between asubset of conductive columns or a subset of conductive rows associatedwith a sensor grid. The comparison component 525 may compare themeasured mutual capacitance between the subset of conductive columns orthe subset of conductive rows to a baseline mutual capacitanceassociated with the set of conductive columns and the set of conductiverows. The determination component 530 may determine a presence of aprotective layer in contact with the surface of the capacitive touchscreen based on the comparison. The adjustment component 535 may adjustan operating characteristic of the sensor grid based on the presence ofthe protective layer in contact with the surface of the capacitive touchscreen.

The transmitter 540 may transmit signals generated by other componentsof the device 505. In some examples, the transmitter 540 may becollocated with a receiver 510 in a transceiver module. For example, thetransmitter 540 may be an example of aspects of the transceiver 720described with reference to FIG. 7. The transmitter 540 may utilize asingle antenna or a set of antennas.

FIG. 6 shows a block diagram 600 of an operations manager 605 thatsupports detection of a protective cover film on a capacitive touchscreen in accordance with aspects of the present disclosure. Theoperations manager 605 may be an example of aspects of an operationsmanager 415, an operations manager 515, or an operations manager 710described herein. The operations manager 605 may include a measurementcomponent 610, a comparison component 615, a determination component620, an adjustment component 625, an identification component 630, and amapping component 635. Each of these modules may communicate, directlyor indirectly, with one another (e.g., via one or more buses).

The measurement component 610 may measure a mutual capacitance between asubset of conductive columns or a subset of conductive rows associatedwith a sensor grid underneath a surface of a capacitive touch screen. Insome examples, the measurement component 610 may determine an ambienttemperature associated with the measured mutual capacitance between thesubset of conductive columns or the subset of conductive rows. In someexamples, the measurement component 610 may measure a touch capacitanceassociated with a touch-point in contact with the surface of thecapacitive touch screen. In some examples, the measurement component 610may add the touch capacitance to the measured mutual capacitance.

The comparison component 615 may compare the measured mutual capacitancebetween the subset of conductive columns or the subset of conductiverows to a baseline mutual capacitance associated with the set ofconductive columns and the set of conductive rows. In some examples, thecomparison component 615 may compare the ambient temperature associatedwith the measured mutual capacitance to a baseline temperatureassociated with the baseline mutual capacitance, where adjusting anoperating characteristic of the sensor grid may be based on thecomparison between the ambient temperature associated with the measuredmutual capacitance and the baseline temperature associated with thebaseline mutual capacitance. In some examples, the comparison component615 may compare the measured mutual capacitance including the touchcapacitance to the baseline mutual capacitance, where determining apresence of a protective layer in contact with the surface of thecapacitive touch screen may be based on the comparison of the measuredmutual capacitance including the touch capacitance to the baselinemutual capacitance. In some cases, the baseline mutual capacitance maybe a manufacturing defined mutual capacitance associated with the set ofconductive columns and the set of conductive rows.

The determination component 620 may determine a presence of a protectivelayer in contact with the surface of the capacitive touch screen basedon the comparison. In some examples, the determination component 620 maydetermine a mutual capacitance offset value based on the comparison. Insome examples, the determination component 620 may determine a presenceof a second protective layer in contact with the surface of thecapacitive touch screen based on the comparison, where adjusting anoperating characteristic of the sensor grid is further based on thepresence of the protective layer and the second protective layer incontact with the surface of the capacitive touch screen. In some cases,the protective layer may be in contact with a first region of thesurface of the capacitive touch screen and the second protective layermay be in contact with a second region of the surface of the capacitivetouch screen different from the first region. In some cases, theprotective layer includes at least one of a polyimide, a polyethylene, aterephthalate, a polyethylene terephthalate polyester, a polyurethane,or a pressure sensitive adhesive, or a combination thereof.

The adjustment component 625 may adjust an operating characteristic ofthe sensor grid based on the presence of the protective layer in contactwith the surface of the capacitive touch screen. In some examples, theadjustment component 625 may adjust a sensitivity or linearity of thesensor grid based on the set of calibration values. In some examples,the adjustment component 625 may calibrate the sensor grid based on theset of calibration values, where adjusting the operating characteristicof the sensor grid is further based on the calibration.

The identification component 630 may identify a set of calibrationvalues corresponding to the protective layer. In some examples, theidentification component 630 may identify a class of the protectivelayer based on the mapping, where adjusting the operating characteristicof the sensor grid is further based on the class of the protectivelayer. In some examples, the identification component 630 may estimate alayer thickness of the protective layer based on the mapping, whereidentifying the class of the protective layer is further based on theestimated thickness of the protective layer.

The mapping component 635 may map the measured mutual capacitance to afirst lookup entry in a set of lookup entries, where the set of lookupentries includes a set of classes of protective layers and a mutualcapacitance corresponding to each class of protective layers. In someexamples, mapping the class of the protective layer to a second lookupentry in the set of lookup entries, where the set of lookup entriesincludes a set of calibration values to compensate for a differencebetween the measured mutual capacitance and the baseline mutualcapacitance. In some examples, mapping the measured mutual capacitanceto a second lookup entry in the set of lookup entries, where the set oflookup entries includes a layer thickness corresponding to the mutualcapacitance of each class of protective layers. In some examples,mapping the estimated layer thickness of the protective layer to a thirdlookup entry in the set of lookup entries, where the set of lookupentries further includes a set of calibration values to compensate for adifference between the measured mutual capacitance and the baselinemutual capacitance. In some examples, mapping the mutual capacitanceoffset value to a second lookup entry in the set of lookup entries,where the set of lookup entries includes a set of calibration values tocompensate for the mutual capacitance offset value associated with adifference between the ambient temperature associated with the measuredmutual capacitance and the baseline temperature associated with thebaseline mutual capacitance, where adjusting the operatingcharacteristic of the sensor grid is further based on the mutualcapacitance offset value.

FIG. 7 shows a diagram of a system 700 including a device 705 thatsupports detection of a protective cover film on a capacitive touchscreen in accordance with aspects of the present disclosure. The device705 may be an example of or include the components of device 405, device505, or a device as described herein. The device 705 may includecomponents for bi-directional voice and data communications includingcomponents for transmitting and receiving communications, including anoperations manager 710, an I/O controller 715, a transceiver 720, anantenna 725, memory 730, a processor 740, and a display 745. Thesecomponents may be in electronic communication via one or more buses(e.g., bus 750).

The operations manager 710 may measure a mutual capacitance between asubset of conductive columns or a subset of conductive rows associatedwith a sensor grid, compare the measured mutual capacitance between thesubset of conductive columns or the subset of conductive rows to abaseline mutual capacitance associated with the set of conductivecolumns and the set of conductive rows, determine a presence of aprotective layer in contact with a surface of the capacitive touchscreen based on the comparison, and adjust an operating characteristicof the sensor grid based on the presence of the protective layer incontact with the surface of the capacitive touch screen.

The I/O controller 715 may manage input and output signals for thedevice 705. The I/O controller 715 may also manage peripherals notintegrated into the device 705. In some cases, the I/O controller 715may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 715 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 715may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 715may be implemented as part of a processor. In some cases, a user mayinteract with the device 705 via the I/O controller 715 or via hardwarecomponents controlled by the I/O controller 715.

The transceiver 720 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 720 may represent a wireless transceiver and may communicatebi-directionally with another wireless transceiver. The transceiver 720may also include a modem to modulate the packets and provide themodulated packets to the antennas for transmission, and to demodulatepackets received from the antennas. In some cases, the device 705 mayinclude a single antenna 725. However, in some cases the device 705 mayhave more than one antenna 725, which may be capable of concurrentlytransmitting or receiving multiple wireless transmissions.

The memory 730 may include RAM and ROM. The memory 730 may storecomputer-readable, computer-executable code 735 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 730 may contain, among otherthings, a BIOS which may control basic hardware or software operationsuch as the interaction with peripheral components or devices.

The code 735 may include instructions to implement aspects of thepresent disclosure, including instructions to support detection of aprotective cover film on a capacitive touch screen. The code 735 may bestored in a non-transitory computer-readable medium such as systemmemory or other type of memory. In some cases, the code 735 may not bedirectly executable by the processor 740 but may cause a computer (e.g.,when compiled and executed) to perform functions described herein.

The processor 740 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 740 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 740. The processor 740 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 730) to cause the device 705 to perform variousfunctions (e.g., functions or tasks supporting detection of a protectivecover film on a capacitive touch screen).

The display 745 may be a resistance touch-based interface, a capacitancetouch-based interface, a surface acoustic wave-based interface, anoptical touch-based interface, an electromagnetic guidance-basedinterface, among others. In some examples, the display 745 may have asurface and a sensor grid underneath the surface having a set ofconductive columns and a set of conductive rows. In some examples, thedisplay 745 may include a liquid-crystal display (LCD), a LED display,an organic LED (OLED), an active-matrix OLED (AMOLED), or the like. Insome examples, the display 745 and I/O component 645 may be or representaspects of a same component (e.g., a touchscreen) of the device 705.

FIG. 8 shows a flowchart illustrating a method 800 that supportsdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure. The operations ofmethod 800 may be implemented by a device or its components as describedherein. For example, the operations of method 800 may be performed by anoperations manager as described with reference to FIGS. 4 through 7. Insome examples, a device may execute a set of instructions to control thefunctional elements of the device to perform the functions describedbelow. Additionally or alternatively, a device may perform aspects ofthe functions described below using special-purpose hardware.

At 805, the device may measure a mutual capacitance between a subset ofconductive columns or a subset of conductive rows associated with asensor grid. The operations of 805 may be performed according to themethods described herein. In some examples, aspects of the operations of805 may be performed by a measurement component as described withreference to FIGS. 4 through 7.

At 810, the device may compare the measured mutual capacitance betweenthe subset of conductive columns or the subset of conductive rows to abaseline mutual capacitance associated with the set of conductivecolumns and the set of conductive rows. The operations of 810 may beperformed according to the methods described herein. In some examples,aspects of the operations of 810 may be performed by a comparisoncomponent as described with reference to FIGS. 4 through 7.

At 815, the device may determine a presence of a protective layer incontact with a surface of the capacitive touch screen based on thecomparison. The operations of 815 may be performed according to themethods described herein. In some examples, aspects of the operations of815 may be performed by a determination component as described withreference to FIGS. 4 through 7.

At 820, the device may adjust an operating characteristic of the sensorgrid based on the presence of the protective layer in contact with thesurface of the capacitive touch screen. The operations of 820 may beperformed according to the methods described herein. In some examples,aspects of the operations of 820 may be performed by an adjustmentcomponent as described with reference to FIGS. 4 through 7.

FIG. 9 shows a flowchart illustrating a method 900 that supportsdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure. The operations ofmethod 900 may be implemented by a device or its components as describedherein. For example, the operations of method 900 may be performed by anoperations manager as described with reference to FIGS. 4 through 7. Insome examples, a device may execute a set of instructions to control thefunctional elements of the device to perform the functions describedbelow. Additionally or alternatively, a device may perform aspects ofthe functions described below using special-purpose hardware.

At 905, the device may measure a mutual capacitance between a subset ofconductive columns or a subset of conductive rows associated with asensor grid. The operations of 905 may be performed according to themethods described herein. In some examples, aspects of the operations of905 may be performed by a measurement component as described withreference to FIGS. 4 through 7.

At 910, the device may compare the measured mutual capacitance betweenthe subset of conductive columns or the subset of conductive rows to abaseline mutual capacitance associated with the set of conductivecolumns and the set of conductive rows. The operations of 910 may beperformed according to the methods described herein. In some examples,aspects of the operations of 910 may be performed by a comparisoncomponent as described with reference to FIGS. 4 through 7.

At 915, the device may determine a presence of a protective layer incontact with a surface of the capacitive touch screen based on thecomparison. The operations of 915 may be performed according to themethods described herein. In some examples, aspects of the operations of915 may be performed by a determination component as described withreference to FIGS. 4 through 7.

At 920, the device may identify a set of calibration valuescorresponding to the protective layer. The operations of 920 may beperformed according to the methods described herein. In some examples,aspects of the operations of 920 may be performed by an identificationcomponent as described with reference to FIGS. 4 through 7.

At 925, the device may adjust a sensitivity or linearity of the sensorgrid based on the set of calibration values. The operations of 925 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 925 may be performed by anadjustment component as described with reference to FIGS. 4 through 7.

FIG. 10 shows a flowchart illustrating a method 1000 that supportsdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure. The operations ofmethod 1000 may be implemented by a device or its components asdescribed herein. For example, the operations of method 1000 may beperformed by an operations manager as described with reference to FIGS.4 through 7. In some examples, a device may execute a set ofinstructions to control the functional elements of the device to performthe functions described below. Additionally or alternatively, a devicemay perform aspects of the functions described below usingspecial-purpose hardware.

At 1005, the device may measure a mutual capacitance between a subset ofconductive columns or a subset of conductive rows associated with asensor grid. The operations of 1005 may be performed according to themethods described herein. In some examples, aspects of the operations of1005 may be performed by a measurement component as described withreference to FIGS. 4 through 7.

At 1010, the device may compare the measured mutual capacitance betweenthe subset of conductive columns or the subset of conductive rows to abaseline mutual capacitance associated with the set of conductivecolumns and the set of conductive rows. The operations of 1010 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1010 may be performed by a comparisoncomponent as described with reference to FIGS. 4 through 7.

At 1015, the device may determine a presence of a protective layer incontact with a surface of the capacitive touch screen based on thecomparison. The operations of 1015 may be performed according to themethods described herein. In some examples, aspects of the operations of1015 may be performed by a determination component as described withreference to FIGS. 4 through 7.

At 1020, the device may determine a presence of a second protectivelayer in contact with the surface of the capacitive touch screen basedon the comparison. The operations of 1020 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1020 may be performed by a determination component asdescribed with reference to FIGS. 4 through 7.

At 1025, the device may adjust an operating characteristic of the sensorgrid based on the presence of the protective layer and the secondprotective layer in contact with the surface of the capacitive touchscreen. The operations of 1025 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1025may be performed by an adjustment component as described with referenceto FIGS. 4 through 7.

FIG. 11 shows a flowchart illustrating a method 1100 that supportsdetection of a protective cover film on a capacitive touch screen inaccordance with aspects of the present disclosure. The operations ofmethod 1100 may be implemented by a device or its components asdescribed herein. For example, the operations of method 1100 may beperformed by an operations manager as described with reference to FIGS.4 through 7. In some examples, a device may execute a set ofinstructions to control the functional elements of the device to performthe functions described below. Additionally or alternatively, a devicemay perform aspects of the functions described below usingspecial-purpose hardware.

At 1105, the device may measure a mutual capacitance between a subset ofconductive columns or a subset of conductive rows associated with asensor grid. The operations of 1105 may be performed according to themethods described herein. In some examples, aspects of the operations of1105 may be performed by a measurement component as described withreference to FIGS. 4 through 7.

At 1110, the device may measure a touch capacitance associated with atouch-point in contact with the surface of the capacitive touch screen.The operations of 1110 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1110may be performed by a measurement component as described with referenceto FIGS. 4 through 7.

At 1115, the device may add the touch capacitance to the measured mutualcapacitance. The operations of 1115 may be performed according to themethods described herein. In some examples, aspects of the operations of1115 may be performed by a measurement component as described withreference to FIGS. 4 through 7.

At 1120, the device may compare the measured mutual capacitance betweenthe subset of conductive columns or the subset of conductive rows to abaseline mutual capacitance associated with the set of conductivecolumns and the set of conductive rows. The operations of 1120 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1120 may be performed by a comparisoncomponent as described with reference to FIGS. 4 through 7.

At 1125, the device may compare the measured mutual capacitanceincluding the touch capacitance to the baseline mutual capacitance. Theoperations of 1125 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1125 may beperformed by a comparison component as described with reference to FIGS.4 through 7.

At 1130, the device may determine a presence of a protective layer incontact with a surface of the capacitive touch screen based on thecomparisons. The operations of 1130 may be performed according to themethods described herein. In some examples, aspects of the operations of1130 may be performed by a determination component as described withreference to FIGS. 4 through 7.

At 1135, the device may adjust an operating characteristic of the sensorgrid based on the presence of the protective layer in contact with thesurface of the capacitive touch screen. The operations of 1135 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1135 may be performed by an adjustmentcomponent as described with reference to FIGS. 4 through 7.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

The description herein provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate.Also, features described with respect to some examples may be combinedin other examples.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other non-transitory medium that can be used tocarry or store desired program code means in the form of instructions ordata structures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include CD, laser disc, optical disc,digital versatile disc (DVD), floppy disk and Blu-ray disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

The phrase “coupled between” may refer to an order of components inrelation to each other, and may refer to an electrical coupling. In oneexample, a component “B” that is electrically coupled between acomponent “A” and a component “C” may refer to an order of components of“A-B-C” or “C-B-A” in an electrical sense. In other words, electricalsignals (e.g., voltage, charge, current) may be passed from component Ato component C by way of component B. A description of a component Bbeing “coupled between” component A and component C should notnecessarily be interpreted as precluding other intervening components inthe described order. For example, a component “D” may be coupled betweenthe described component A and component B (e.g., referring to an orderof components of “A-D-B-C” or “C-B-D-A” as examples), while stillsupporting component B being electrically coupled between component Aand component C. In other words, the use of the phrase “coupled between”should not be construed as necessarily referencing an exclusivesequential order. Further, a description of component B being “coupledbetween” component A and component C does not preclude a second,different coupling between component A and component C. For example,component A and component C may be coupled with each other in a separatecoupling that is electrically parallel with a coupling via component B.In another example, component A and component C may be coupled viaanother component “E” (e.g., component B being coupled between componentA and component C and component E being coupled between component A andcomponent C). In other words, the use of the phrase “coupled between”should not be construed as an exclusive coupling between components.

The term “layer” used herein refers to a stratum or sheet of ageometrical structure. Each layer may have three dimensions (e.g.,height, width, and depth) and may cover some or all of a surface. Forexample, a layer may be a three-dimensional structure where twodimensions are greater than a third, such as a thin-film. Layers mayinclude different elements, components, and/or materials. In some cases,one layer may be composed of two or more sublayers. In some of theappended figures, two dimensions of a three-dimensional layer aredepicted for purposes of illustration. Those skilled in the art will,however, recognize that the layers are three-dimensional in nature.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

As used herein, the phrase “based on” shall not be construed as areference to a closed set of conditions. For example, an exemplary stepthat is described as “based on condition A” may be based on both acondition A and a condition B without departing from the scope of thepresent disclosure. In other words, as used herein, the phrase “basedon” shall be construed in the same manner as the phrase “based at leastin part on.”

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. An apparatus, comprising: a processor, acapacitive touch screen in electronic communication with the processor,the capacitive touch screen comprising a surface and a fingerprintsensor underneath the surface, memory in electronic communication withthe processor, and instructions stored in the memory and executable bythe processor to cause the apparatus to: determine a presence of aprotective layer in contact with the capacitive touch screen; and adjustan operating characteristic of the fingerprint sensor based at least inpart on the presence of the protective layer in contact with thecapacitive touch screen.
 2. The apparatus of claim 1, wherein theinstructions to adjust the operating characteristic of the fingerprintsensor are further executable by the processor to cause the apparatusto: adjust one or more of a sensitivity or a linearity of a subset ofconductive elements of the fingerprint sensor based at least in part ona set of calibration values corresponding to the protective layer. 3.The apparatus of claim 1, wherein the instructions are furtherexecutable by the processor to cause the apparatus to: identify a classof the protective layer based at least in part on a lookup table,wherein the instructions to adjust the operating characteristic of thefingerprint sensor are further executable by the processor based atleast in part on the class of the protective layer.
 4. The apparatus ofclaim 3, wherein the lookup table comprises a set of classes ofprotective layers and a capacitance corresponding to each class ofprotective layers.
 5. The apparatus of claim 3, wherein the instructionsare further executable by the processor to cause the apparatus to:calibrate a subset of conductive elements of the fingerprint sensorbased at least in part on the class of the protective layer, wherein theinstructions to adjust the operating characteristic of the fingerprintsensor are further executable by the processor based at least in part onthe calibration.
 6. The apparatus of claim 3, wherein the instructionsare further executable by the processor to cause the apparatus to:estimate a layer thickness of the protective layer based at least inpart on mapping the class of the protective layer to an entry in thelookup table, wherein the instructions to identify the class of theprotective layer are further executable by the processor based at leastin part on the estimated layer thickness of the protective layer.
 7. Theapparatus of claim 6, wherein the entry in the lookup table comprises alayer thickness corresponding to the class of the protective layer. 8.The apparatus of claim 6, wherein the instructions are furtherexecutable by the processor to cause the apparatus to: calibrate asubset of conductive elements of the fingerprint sensor based at leastin part on the estimated layer thickness of the protective layer,wherein the instructions to adjust the operating characteristic of thefingerprint sensor are further executable by the processor based atleast in part on the calibration.
 9. The apparatus of claim 3, whereinthe instructions are further executable by the processor to cause theapparatus to: determine an ambient temperature between a subset ofconductive elements of the fingerprint sensor; and compare the ambienttemperature to a baseline temperature, wherein the instructions toadjust the operating characteristic of the fingerprint sensor arefurther executable by the processor based at least in part on thecomparison between the ambient temperature and the baseline temperature.10. The apparatus of claim 9, wherein the instructions are furtherexecutable by the processor to cause the apparatus to: determine acapacitance offset value based at least in part on the comparisonbetween the ambient temperature and the baseline temperature; and mapthe capacitance offset value to an entry in the lookup table, whereinthe instructions to adjust the operating characteristic of thefingerprint sensor are further executable by the processor based atleast in part on the capacitance offset value.
 11. The apparatus ofclaim 1, wherein the protective layer comprises at least one of apolyimide, a polyethylene, a terephthalate, a polyethylene terephthalatepolyester, a polyurethane, or a pressure sensitive adhesive, or acombination thereof.
 12. A method comprising: determining a presence ofa protective layer in contact with a capacitive touch screen; andadjusting an operating characteristic of a fingerprint sensor associatedwith the capacitive touch screen based at least in part on the presenceof the protective layer in contact with the capacitive touch screen. 13.The method of claim 12, wherein adjusting the operating characteristicof the fingerprint sensor comprises: adjusting one or more of asensitivity or linearity of a subset of conductive elements of thefingerprint sensor based at least in part on a set of calibration valuescorresponding to the protective layer.
 14. The method of claim 12,further comprising: identifying a class of the protective layer based atleast in part on a lookup table, wherein adjusting the operatingcharacteristic of the fingerprint sensor is further based at least inpart on the class of the protective layer.
 15. The method of claim 14,further comprising: calibrating a subset of conductive elements of thefingerprint sensor based at least in part on the class of the protectivelayer, wherein adjusting the operating characteristic of the fingerprintsensor is further based at least in part on the calibration.
 16. Themethod of claim 14, further comprising: estimating a layer thickness ofthe protective layer based at least in part on mapping the class of theprotective layer to an entry in the lookup table, wherein identifyingthe class of the protective layer is further based at least in part onthe estimated layer thickness of the protective layer.
 17. The method ofclaim 16, further comprising: calibrating a subset of conductiveelements of the fingerprint sensor based at least in part on theestimated layer thickness of the protective layer, wherein adjusting theoperating characteristic of the fingerprint sensor is further based atleast in part on the calibration.
 18. The method of claim 14, furthercomprising: determining an ambient temperature between a subset ofconductive elements of the fingerprint sensor; and comparing the ambienttemperature to a baseline temperature, wherein adjusting the operatingcharacteristic of the fingerprint sensor is further based at least inpart on the comparison between the ambient temperature and the baselinetemperature.
 19. The method of claim 18, further comprising: determininga capacitance offset value based at least in part on the comparisonbetween the ambient temperature and the baseline temperature; andmapping the capacitance offset value to an entry in the lookup table,wherein adjusting the operating characteristic of the fingerprint sensoris further based at least in part on the capacitance offset value. 20.An apparatus, comprising: means for determining a presence of aprotective layer in contact with a capacitive touch screen; and meansfor adjusting an operating characteristic of a fingerprint sensorassociated with the capacitive touch screen based at least in part onthe presence of the protective layer in contact with the capacitivetouch screen.